Over 10 million people in the U.S. -- about one in 30 -- are cancer survivors. This growing population reflects advances in cancer detection and treatment. But with the greater number of survivors comes an increasing number of people living long enough to experience more than one type of cancer in their lifetime. Overall, cancer survivors have a 14 percent higher risk of developing a new primary malignancy compared with the general population, according to a new NCI monograph entitled, New Malignancies among Cancer Survivors: SEER Cancer Registries, 1973-2000. The risk factors involved in the second cancer may be the same as those that led to the original tumor, such as smoking, excessive alcohol use, diet and nutrition, and genetic predisposition. For some people, however, the radiotherapy or chemotherapy received to treat the first cancer may be a contributing factor for their developing a completely new primary cancer.

While some cancer survivors are more likely to develop a new tumor than others, little is known about the complex interaction of factors that lead to this increase in risk. The chance of developing a second cancer can be affected by a variety of factors, including shared causal factors, such as lifestyle and environmental exposures, genetic susceptibility, and combinations of risk factors including gene-gene and gene-environment interactions. As more research focuses on the issues faced by cancer survivors, scientists hope to provide answers that will allow for improved therapy and care. Researchers also believe that knowledge gained from these studies will improve the quality of life for all cancer patients.